textproduct: Quad Cities

KEY MESSAGES

- Impactful heat will continue across the area through Saturday with peak heat indices of 100 to 110. The heat warnings may need to be expanded Saturday into the I-80 corridor east of the Quad Cities.

- There will be brief reprieves from the heat late this weekend and late next week. Another surge of heat and humidity with heat indices around 100 is expected the middle of next week. The overall pattern has a 55-70% probability of above normal temperatures through mid- September.

- There is a daily risk of showers and storms, mainly along and north of I-80. While there is a risk of rain, there will be plenty of dry hours.

SHORT TERM /THROUGH TONIGHT/

Issued at 143 AM CDT Fri Sep 4 2026

Another day of heat and humidity for the area with peak heat indices ranging from 100 to 110 this afternoon. The current headlines still look good for today.

Internally, a couple of the very short range models are attempting to develop some nocturnal convection at the nose of the LLJ across far northern Iowa before sunrise. As of yet satellite is not showing any indication of this happening, but the overall timing was 2-5 AM.

IF this convection develops as suggested, most of it will remain north of the area. With the progged development a tad further south than yesterday, there is a low chance (10-20%) of some showers or a thunderstorm getting into the Highway 20 corridor 6-11 AM. Like yesterday, the REFS has showers and storms festering along the boundary through the day with some activity potentially occurring in the Highway 20 corridor during the afternoon.

Tonight, another disturbance will ride along the edge of the heat dome. This disturbance will develop the next round of nocturnal showers and storms. Unlike the previous nights, this disturbance may push some showers/storms into the northeast parts of the area. The key message here is that any convection would be low on coverage, 10- 30 percent.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 143 AM CDT Fri Sep 4 2026

Saturday/Saturday night Assessment...a certainty (>95%) of heat and humidity

The impactful heat and humidity will continue through Saturday. Areas north of I-80 will see peak afternoon heat indices of 95-100. Along the I-80 corridor and south, peak afternoon heat indices will be over 100 again. The extreme heat warning may need to be extended into the I-80 corridor east of the Quad Cities.

While an isolated rogue shower or storm cannot be ruled out, especially north of I-80. The first part of the holiday weekend looks to be dry.

Sunday through Thursday Assessment...very high (>80%) confidence on above normal temperatures.

The upper level ridge retrogrades briefly into the Plains for the second half of the holiday weekend but will then push back east for the middle of next week. Thus after a brief reprieve from the heat Sunday/Monday, heat and humidity will surge back into the area Tuesday/Wednesday with heat indices approaching 100.

By late next week the overall flow pattern aloft de-amplifies slightly. This will allow temperatures to be closer to but still above normal.

Any rain chances the first half of next week are low (10-25%) and are confined to areas along/north of I-80. Thus there will be many hours of dry weather.

The models are attempting to bring a front into the area Tuesday night into Wednesday with the front progged to stall and wash out across the area. The proximity of the front has the model consensus giving slightly higher rain chances (30-50%) for late Tuesday night.

Once the front stalls and washes out across the area, its remnants would then provide the focus for rain chances the remainder of the week. However, even with a near daily chance of rain, the rain chances remain low (20-30%) with the better forcing remaining across the northern Plains and upper Midwest.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1210 AM CDT Fri Sep 4 2026

Winds will be around 5 knots or less through sunrise. After sunrise winds will increase to 5-10 knots with density altitudes approaching or exceeding 3 kft by 18z. There is a 10 percent chance of a SHRA or even a stray TSRA impacting KDBQ 12z-15z/04. After sunset winds will again drop to 5 knots or less from the south.

CLIMATE

Issued at 558 AM CDT Thu Sep 3 2026

The Quad Cities (MLI) has had two days to start this month with 95 degree highs. If a third happens today, it would be the longest such stretch in September since September 4-6, 1990.

Record Warm Low Temperatures:

September 3: KDBQ: 73/1939 KMLI: 76/1939

September 4: KDBQ: 71/1912 KMLI: 74/2018

September 5: KDBQ: 76/1881 KMLI: 76/1925

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory until 7 PM CDT this evening for IAZ040>042- 051>054-066. Extreme Heat Warning until 7 PM CDT Saturday for IAZ063>065- 067-068-076>078-087>089-098-099. IL...Heat Advisory until 7 PM CDT this evening for ILZ001-002-007- 009. Extreme Heat Warning until 7 PM CDT Saturday for ILZ015- 024>026-034-035. Extreme Heat Warning until 7 PM CDT this evening for ILZ016>018. MO...Extreme Heat Warning until 7 PM CDT Saturday for MOZ009-010.